Characteristics and Geomorphic Relationships of Some Representative Aridisols in Southern Iran

Abstract

The morphology, genesis, and classification of three soils, each located on different physiographic positions, were investigated in southern Iran. These soils were: pedon 1, Beyza series on the Piedmont Alluvial Plain; pedon 2, Takht‐E‐Jamshid (Persepolis) series on the Upland Alluvial Plain; and pedon 3, Kooshkak (Jamalabad) series on the Lowland Alluvial Plain. These series represent 57% of the total study area (77 000 ha). The soils are calcareous throughout with carbonate concretions, nodules, and powdery pockets present in pedons 2 and 3. Clay skins are indicated in the B horizons of pedon 2. Soil pH rises from the Piedmont to the Lowland Alluvial Plain whereas organic matter decreases. Electrical conductivity does not show a regular trend from the Piedmont to the Lowland Alluvial Plain. Results of X‐ray diffraction analyses of < 2 µm clay indicate that the soils contain regularly interstratified smectite‐vermiculite and/or chlorite, clay mica‐vermiculite or chlorite, and some discrete vermiculite, chlorite, clay mica, kaolinite, and quartz. Evidence for attapulgite is also suggested. Tentatively, pedon 1 is classified as a Fluventic or Xerollic Camborthid; pedon 2a Xerollic or Typic Calciorthid; and pedon 3 a Xerollic Haplargid or Calciorthid.